Early diagnosis of non-alcoholic fatty liver disease (NAFLD) is important.
Up to 25% of people with NAFLD go on to develop non-alcoholic steatohepatitis (NASH), which may progress to cirrhosis. But if NAFLD is detected and treated early, permanent liver damage and life-threatening disease can be avoided.
Your doctor will use your medical history, a physical examination and tests to diagnose NAFLD.
He or she will check in on your weight and physical activity levels, and ask you about your diet and other lifestyle habits. During the physical examination, your doctor will check for signs of insulin resistance (e.g. darkened skin in your neck or armpits), cirrhosis and an enlarged liver.
Tests may be used to determine if you have any underlying conditions, if you have elevated liver enzyme levels, and if there is indeed a build-up of fat in the liver (and how significant it is).
These tests may include:
- A full blood count
- Liver function tests
- Lipid profile tests
- Tests for chronic viral hepatitis (hepatitis A, B, C and others)
- A fasting blood glucose test
- An abdominal ultrasound scan
- A computerised tomography (CT) scan
- A magnetic resonance imaging (MRI) scan
Your doctor may also perform tests and examinations to rule out the possibility of other conditions (e.g. Wilson’s disease and drug-induced liver disease).
If your doctor suspects that you have NAFLD or NASH, he or she may do a biopsy to assess the severity of the inflammation and scarring in your liver. During a biopsy, a sample of tissue will be removed from your liver and sent off for examination in a pathology lab.
Biopsy is the only test that can distinguish NASH from other forms of liver disease, and is the gold standard for diagnosing NAFLD. Note, however, that biopsy is usually reserved for people who are at high risk of NASH, e.g. those who are obese, older than 45 years of age and/or insulin resistant (or who already have type 2 diabetes).
Newer, non-invasive tests are also becoming more widely available. These tests either measure levels of disease biomarkers in the blood (e.g. the NAFLD fibrosis score) or liver stiffness (e.g. transient elastography). The machine used for transient elastography (e.g. FibroscanR) may have built-in functionality called “CAP” that can non-invasively measure fatty change in the liver. Note that you will be referred to a hepatologist, a doctor who specialises in liver disease, if you have NASH.
Reviewed by Dr Mark Sonderup, B Pharm, MB ChB, FCP (SA). Senior Specialist, Division of Hepatology, Department of Medicine, University of Cape Town and Groote Schuur Hospital. July 2018.